That alone may not sound like a big deal. It becomes interesting once you repeat the question: "I know B is often bought with A. But what is most commonly bought with B?" Suddenly patterns begin to emerge, and clusters appear:

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Business Model/Value Proposition

“In a startup, the founders define the product vision and then use customer discovery to find customers and a market for that vision.”

“When customers enthusiastically confirm the importance of both the problem and the solution, customer discovery is complete.”

“Products developed by founders who get out in front of customers early and often, win.”

“To succeed, founders need to turn hypotheses or guesses into facts as soon as possible by getting out of the building, asking customers if the hypotheses were correct, and quickly changing those that were wrong.”

“Customer discovery includes two outside-the-building phases. The first tests customer perception of the problem and the customer’s need to solve it.”

“An organization must make a conscious decision about which segments to serve and which segments to ignore.”

“The Value Proposition is the reason why customers turn to one company over another. It solves a customer problem or satisfies a customer need.”

“We believe a business model can best be described through nine basic building blocks that show the logic of how a company intends to make money. The nine blocks cover the four main areas of a business: customers, offer, infrastructure, and financial viability. The business model is like a blueprint for a strategy to be implemented through organizational structures, processes, and systems.”

“A business model describes the rationale of how an organization creates, delivers, and captures value”

“The Channels Building Block describes how a company communicates with and reaches its Customer Segments to deliver a Value Proposition”

“Pains describe anything that annoys your customers before, during, and after trying to get a job done or simply prevents them from getting a job done.”

“Jobs describe the things your customers are trying to get done in their work or in their life. A customer job could be the tasks they are trying to perform and complete, the problems they are trying to solve, or the needs they are trying to satisfy.”

“Gains describe the outcomes and benefits your customers want. Some gains are required, expected, or desired by customers, and some would surprise them. Gains include functional utility, social gains, positive emotions, and cost savings.”

“The Value (Proposition) Map describes the features of a specific value proposition in your business model in a more structured and detailed way. It breaks your value proposition down into products and services, pain relievers, and gain creators.”

Management

“Disruptive technologies bring to a market a very different value proposition than had been available previously. Generally, disruptive technologies underperform established products in mainstream markets. But they have other features that a few fringe (and generally new) customers value. Products based on disruptive technologies are typically cheaper, simpler, smaller, and, frequently, more convenient to use.”

“Visionaries are not looking for an improvement; they are looking for a fundamental breakthrough.”

“the key to getting beyond the enthusiasts and winning over a visionary is to show that the new technology enables some strategic leap forward, something never before possible, which has an intrinsic value and appeal to the nontechnologist.”

“If two people buy the same product for the same reason but have no way they could reference each other, they are not part of the same market.”

“Marketing professionals insist on market segmentation because they know that no meaningful marketing program can be implemented across a set of customers who do not reference each other.”

“One of the most important lessons about crossing the chasm is that the task ultimately requires achieving an unusual degree of company unity during the crossing period.”

“Executives must answer three sets of questions to determine whether an idea has disruptive potential.”

“Predictable marketing requires an understanding of the circumstances in which customers buy or use things.”

“Is the innovation disruptive to all of the significant incumbent firms in the industry? If it appears to be sustaining to one or more significant players in the industry, then the odds will be stacked in that firm’s favor, and the entrant is unlikely to win.”

“Once the disruptive product gains a foothold in new or low-end markets, the improvement cycle begins.”

“Disruptive innovations, in contrast, don’t attempt to bring better products to established customers in existing markets. Rather, they disrupt and redefine that trajectory by introducing products and services that are not as good as currently available products. But disruptive technologies offer other benefits—typically, they are simpler, more convenient, and less expensive products that appeal to new or less-demanding customers.”

Investment and Ventures

“In the summary, include the problem you are solving and why it's important to solve. Explain why your product is awesome, why it's better than what currently exists, and why your team is the right one to pursue it. End with some high-level financial data to show that you have aggressive, but sensible expectations about how your business will perform over time.”

“the problem you are solving, the size of the opportunity, the strength of the team, the level of competition or competitive advantage that you have, your plan of attack, and current status. Summary financials, use of proceeds, and milestones are also important. Most good investor presentations can be done in 10 slides or fewer.”

“Instead, focus on a length of time you want to fund your company to get to the next meaningful milestone.”

“We believe the demo, a prototype, or an alpha is far more important than a business plan or financial model for a very early stage company.”

“Start with an attitude of presuming success. If you don’t, investors will smell this uncertainty on you; it'll permeate your words and actions.”

“There are three building blocks that drive valuations: (1) Financial performance including revenues, growth, and earnings; (2) Product/service/distribution; (3) Team.”

“When you are deciding which company to invest in as an angel or VC, I would advise you to look first at the management, then at the size of the market, and then after these two look at the idea or technology.”

“It is a fair question for an entrepreneur to ask VCs at what stage they are in the life cycle of their fund and what are the dynamics of looking for new investments?”

“In the Silicon Valley and New York City, the most common amount of angel funding that entrepreneurs seek is $500,000, $750,000, or $1.5 million.”

“Typically in the Valley, angels form a syndicate to deposit a total of $500,000 into the company’s bank account on a convertible note with a discount rate of 15 to 35 percent and a cap of $3 to $5 million.”

“The calculation of pre-money value should be the result of multiplying the total number of shares outstanding, including warrants and issued options, by the price per share that is offered in the term sheet. The post-money valuation is determined by adding the total amount to be raised in equity in the round of financing contemplated by the term sheet to the pre-money valuation.”

“But it is wiser for entrepreneurs to seek funding which will last them 12 to 18 months in competitive financing environments.”

“Price per share is important because it embodies the economic value of where the company is today.”

“There are, however, five basic forms and styles of term sheets. These are typically attributable to the leading venture legal firms: Cooley; Hale and Dorr; Mintz-Levin; Testa, Hurwitz and Thibeault; and Wilson-Sonsini.”

“Angels are typically buying common stock, the same class of stock owned by founders.”

Marketing

“Figure out how to make money. Figure out what kind of people you need to attract to make money. Figure out what those people want to read (which is probably different from what you want them to read).”

“Our experience is that the sweet spot for posts of curated content is two or three sentences on Google+ and Facebook and one hundred characters on Twitter. The sweet spot for created content is five hundred to a thousand words.”

“Every post—literally every single post—should contain “eye candy” in the form of a picture, graphic, or video.”

“My theory is that if you’re not pissing people off on social media, you’re not using it right.”

“Content curation involves finding other people’s good stuff, summarizing it, and sharing it. Curation is a win-win-win: you need content to share; blogs and websites need more traffic; and people need filters to reduce the flow of information.”

“They define Upworthy content as content being at an intersection of awesome, relevant, and visual.”

“Regardless of the type of community you’re engaging, your best role is to be a trusted expert within the community.”

“Engagement Marketing, Nurture Marketing, and Social IMC. IMC stands for Integrated Marketing Communications and represents a database-driven, 1-to-1 relationship between an organization and an individual.”

“what visitors really want is content that first describes the issues and problems they face and then provides details on how to solve those problems.”

“When people come to you online, they are not looking for TV commercials. They are looking for information to help them make a decision.”

“Get down to the essence of what your product solves and write good stories about that and publish them online.”

“The web is different. Instead of one-way interruption, web marketing is about delivering useful content at just the precise moment a buyer needs it. It's about interaction, information, education, and choice.”

“Every business has information that can contribute to the education of the marketplace. You need to ask yourself, ‘How can I get that information out there?”

Discoveries that are not so obvious

Wow! All that information was available by just looking at the network. It clearly tells us about communities behind Lean Startup. But there is more. Take a look at the graph once again. Do you see anything missing?

It's hard to see, because I'm asking about something that is not really there...

If we take the most popular books within every cluster, we'll notice that sometimes there is no direct connection between these books. A missing link. A blank space between two popular products. For example: